Mechanism for clamping flexible printing plates to the plate cylinder of machines for flat printing



Nov. 3, 1959 M. MOSEGAARD 2,910,939

CLAMPI PLATES MECHANISM FOR NG FLEXIBLE PRINT TO THE PLATE C NDER OFMACHI FOR FL PRINTING Fig.1

Filed June 23, 1958 4 Sheets-Sheet 1 Fig.2

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r ll 22 Nov. 3, 1959 M. M EGAAR 2,910,939

MECHANISM FOR C P1 FLEXIBLE INTING PLATES TO THE P TE CYLINDER MACHINESFOR FLAT PRIN G Filed June 23, 1958 4 Sheets-Sheet 2 73 A 3/2 79 0c B//6 Fig, 6 52 Ty e d 6'4 22 @pefi 7' e B 52 50 54 I 48 fifvENToR.

Nov. 3, 1959 M. MOSEGAARD 2,910,939

MECHANISM FOR CLAMPING FLEXIBLE PRINTING PLATES TO L T Filed June 23,1958 wgx Mar/w M0J644Aw BY 19M x1 Wm Nov. 3, 1959 M. MOSEGAARD 2,910,939

MECHANISM FOR CLAMPING FLEXIBLE FRI NG PLATES TO THE PLATE CYLINDER OFMAC INES FOR FLAT PRINTING Filed June 23, 1958 Fig.8 42 91 4Sheets-Sheet. 4

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MAE/(A9 Moa amea BY United States Patent MECHANISM FOR CLAMPING FLEXlBLEPRINT- ING PLATES TO THE PLATE CYLINDER OF MACHINES FOR FLAT PRINTING 3Claims. (Cl. 101-415.1)

Denmark, assignor to Denmark, a Danish This invention relates to amechanism for clamping flexible printing plates to the plate cylinder ofmachines, particularly high-speed rotary machines, for flat printing,preferably offset printing, wherein the ends of the printing plate areconnected to two rails or lists which are received in an axiallyextending recess or groove in the circumferential surface of thecylinder.

Such mechanisms have been made in many different ways. It has beensuggested to place wedge pieces behind the lists, which wedges cooperatewith inclined surfaces in the cylinder recess and press against the rearsides of the lists so as to move same in tangential direction during thetightening of the printing plate. The wedge pieces may e.g. beinfluenced by means of screws, which are placed radially inthe cylinderrecess and force the wedge pieces outwards. Such a mechanism has provedexpedient in practice, although the construction becomes rathercomplicated.

According to the present invention a' more simple construction isobtained by placing transversely of the rails a number of shafts, eachof which is mounted in bores in both rails and carries an adjusting discin the slot between the rails, the ends of the shafts cooperating withthe walls limiting the groove or recess so that by turning the shaftsthe rails can be adjusted indifferent directions within the spaceconfined by the walls of the groove.

This rather universal adjustment can be obtained thereby that some ofthe shafts are threaded at one or the other side of the adjusting disc,and that said screw threads cooperate with screw threads in thecorresponding bore in the rail, while the other end or both ends of theshaft abut against one of the walls or both walls limiting the groove oragainst abutment pieces positioned here. Said shafts can be used. toadjust the rails in tangential direction to one or the other side.According to the invention an adjustment of the rails in theperpendicular direction, i.e. in a plane through the axis of thecylinder, is obtained by the measure that some others of the shafts aremounted in smooth bores in either rail and at both ends have eccentricjournals, which cooperate with axially extending abutment faces in thewalls limiting the groove or with slide blocks, which are displaceablein axially extending grooves in said walls.

Other characteristic features of the invention will appear from thefollowing description with reference to the drawings, which depict oneembodiment of the mechanism according to the invention.

Figures 1 and 2 show an axial section through a plate cylinder for arotary machine, taken at the circumference centrally through the groovewhich receives said mechanism, said section extending through half thelength of the cylinder only,

Figures 3 and 4 show on a larger scale part of the mechanism as seenfrom the outer side of the cylinder,

Figures 5 and 6 are a section of same along a plane perpendicular to anaxial plane through the center of the groove, and

ice

Figures 7, 8, 9 and 10 show on a larger scale sections along the linesIV--IV, V-V, VIVI, and VIIVII, respectively, in Figure 2.

In the surface of the plate cylinder 10 an axially extending groove orrecess 12 with substantially rec tangular cross section is provided. Atthe ends of the cylinder this recess is terminated by means of rings 14,which in known manner are attached to the end faces of the cylinder. Atthe sides of the recess two bars 16 are inserted, which are attached bymeans of screws 20, see Figure 10, to a bar 18, situated at the bottomof the recess, whereupon the bar 18 is attached to the cylinder 10 bymeans of screws 22, see Figures 1 and 2. At the top of their sidesfacing inwards the bars 16 have inclined surfaces 24, so that the threebars 16, 16, and 18 together will form an undercut groove 26, whoseaperture at the surface of the cylinder is a narrow slit 28. In thisgroove two rails 30 and 32 are disposed, which in the outward directiontowards the surface of the cylinder are wedge-shaped by means ofinclined surfaces 34, Figure 10, extending from their side facingoutwards towards their side facing inwards in the same direction as theappertaining inclined surfaces 24. The rails 30 and 32 serve to fastenthe ends of a flexible plate 36 which consists of suitable metal, e.g.stainless steel, and which constitutes the printing plate.

For attaching the edges 40 of the plate 36 to the rails 30 and 32 theselatter have on their surfaces facing each other narrow axially extendinggrooves 38 which receive the bent edges 44 of the printing plate whichis bent also at the circumference of the plate cylinder and extendsinwardly through the slit 28 to the grooves 38.

For the adjustment of the rails 30 and 32 in different direction withinthe clearance between same and the wall surfaces of the groove 26 anumber of adjusting discs 42 are used, which are so thin that they canbe received'in the narrow slit between said rails, and which at eitherside have shafts 44 disposed in continuation of each other. The disc andthe shafts are preferably integral.

The said discs are distributed throughout the length of.

the groove 26 in groups of five, as will be seen from Figures 1 and 2.

The shafts 44 are mounted in bores, in both rails 30 and 32, but indifferent ways so as to serve different purposes, as will appear fromthe following. Three different type are provided, A, B, and C, shown inFigures 7, 9 and 8, respectively.

As regards type A the left-side shaft 44, Figure 7, has screw threads46, which cooperate with corresponding screw threads in the rail 30,whereas the right-side shaft is smooth and is received in acorresponding smooth bore in the rail 32. The end faces of the twoshafts 44 abut against abutment pieces 43, which are inserted incorresponding recesses in the bars 16. When the adjusting disc 42 isturned, the rail 30 will be displaced to the right or to the left,depending on the direction of rotation, as the shafts 44 cannot beaxially displaced, because their end faces rest against the pieces 48.

Type B, shown in Figure 9, is identical with type A, the only differencebeing that it is the right-side shaft 44 which is provided with screwthreads 46 cooperating with screw threads in the rail 32, whereas theother shaft is smooth. This makes it possible to adjust this rail to theright and to the left by turning the disc 42.

As regards type C, both shafts 44 are smooth and mounted in smooth boresin the rails 30 and 32, see Figure 8. At their ends both shafts haveeccentric journals 50, which are received in bores in slide blocks 52being displaceable in short axially extending grooves 54 in the bars 16,see Figures 5 and 6. When the disc 42 is turned, both rails 30 and 32can be displaced downwardly from the position shown in Figures 1-2 and 8eccentricity of the journals 50 in relation to the shafts 44.Simultaneously, the blocks 52 reciprocate slightly in the grooves 54.

For each group of adjusting means the various types are placed in thesuccession shown in Figures 5 and 6 with type A and type B being closelyjuxtaposed at either end of the group, and type C being found at thecenter of the group. By using the adjusting means of type A and type Bthe rails 30 and 32, respectively, and consequently the edges of theprinting plate 36 can be adjusted to either side, so that it is possibleto obtain an exact registration. Besides, by these adjusting means atightening of the printing plate can be obtained. The final tighteningof this plate is effected with the adjusting means of type C bysimultaneous lowering of the rails 30 and 32, whereby it is also ensuredthat no parts will protrude at the mouth of the slit 28.

As several groups of adjusting means are provided, it will be possibleto obtain a very even and uniform clamping and tightening of theprinting plate.

In the shown embodiment the adjusting discs 42 are provided at theircircumference with notches 56, so that they can be turned by means of ahook spanner, not shown, which is introduced through the slit 2%.

By the engagement of the bent edges 46 of the printing plate 36 with thegrooves 38 in the rails 30 and 32, a suflicient securing of the printingplate is obtained, without any need for soldering or spot welding.Therefore, when removing or fixing the printing plate it is notnecessary to remove the rails from the groove 26.

It is to be understood that the invention is not to be limited to theembodiment shown in the drawing, as obvious modifications will beapparent to one skilled in the art and the invention is therefore to belimited only by the scope of the appended claims.

Having thus fully described my invention I claim as new and desire tosecure by Letters Patent:

1. A plate cylinder for rotary printing machines, comprising a pair ofgroove defining walls extending axially of said cylinder andsubstantially parallel to a plane through the axis of said cylinder,printing plate clamping means arranged within said groove, a printingplate mounted on the cylindrical surface of said cylinder and havingaxially extending edges to be secured by said clamping means within saidgroove, an adjustment device for adjusting the relative position of saidclamping means being provided within said groove between said clampingmeans, said adjustment device including a plurality of discs rotatablewith shafts supported by said clamping means, alternative ends of saidshafts being threaded to cooperate with threads in association with oneor other of said clamping means, and at least one disc formed with asmooth shaft penetrating through said clamping means and terminating injournals being eccentric in relation to the shaft, bearings for saidjournals being provided in the walls of the groove extending axial atthe surface of the plate cylinder, said bearings being axially slidable.

2. A plate cylinder for rotary printing machines, comprising parallelwalls defining an axially extending,

groove, adjustable rails within said groove being spaced to leave a gaptherebetween, a flexible printing plate including edges extending intosaid gap, clamping means provided on said rails facing said gap andarranged to secure said printing plate edges, adjusting devicesassociated with said rails for radial and peripheral adjustment thereof,said adjusting devices each comprising a disc mounted within said gapwith a disc-carrying shaft extending normal to the axial direction andto the radius of said plate cylinder, the ends of said shaft beingeccentrically offset in relation to the shaft proper, and bearings forsaid offset shaft ends provided in the groovedeiining walls so as toallow for a limited movement of the bearings in response to adjustmentof the rails.

3. A plate cylinder for rotary printing machines, comprising a pair ofgroove-defining walls extending axially of said cylinder andsubstantially parallel to a plane through the axis of said cylinder,printing plate clamping means arranged within said groove, a printingplate mounted on the cylindrical surface of said cylinder and havingaxially extending edges to be secured by said clamping means within saidgroove, an adjustment device for adjusting the relative position of saidclamping means being provided within said groove between said clampingmeans, said adjustment device including a plurality of discs rotatablewith shafts supported by said clamping means, alternative ends of saidshafts being threaded to cooperate with threads in association with oneor other of said clamping means, and at least one disc formed with asmooth shaft penetrating through said clamping means and terminating injournals being eccentric in relation to the shaft, bearings for saidjournals beingv provided in the walls of the groove extending axial atthe surface of the plate cylinder.

References Cited in the file of this patent UNITED STATES PATENTS GreatBritain Sept. 5, 1956 i

